The Spanish verb 'explicar' (to explain) comes from the Latin word 'explicare', which literally meant 'to unfold' or 'to explain'. The Latin word was formed by combining two elements: the prefix 'ex-' meaning 'out' or 'outward', and the verb 'plicare' meaning 'to fold'. When combined, these elements created the metaphorical meaning of 'unfolding' something to make it clear or understandable - just as you might unfold a piece of paper to reveal what's written inside.

Several common Spanish words share the Latin root 'plicare' (to fold). Some related words include 'plegar' (to fold), 'desplegar' (to unfold or deploy), and 'aplicar' (to apply). Just as 'explicar' means to unfold something in the sense of making it clear, 'desplegar' literally means to unfold something physically, while 'aplicar' suggests folding or putting something onto something else.

Many English words are related to 'explicar' through the same Latin roots. The most obvious is 'explain', which comes from the same Latin 'explicare'. Other related English words include 'explicit' (clearly unfolded or expressed), 'explicate' (to analyze in detail), and words containing 'plic-' like 'complicate' (to fold together), 'implicate' (to fold in), and 'duplicate' (to fold double). The physical act of folding evolved into various metaphorical meanings in both languages.